The role of proteolytic enzymes in demyelination in experimental animal models will be further investigated. A neutral proteinase which hydrolyzes only basic proteins has been identified in lymph nodes of Lewis rats with acute experimental allergic encephalomyelitis (EAE). The activity of this enzyme in lymph nodes in susceptible Lewis rats and non-susceptible Wistar rats in various stages of EAE compared with the Freund's adjuvant control will be measured. The enzyme will be further purified and its characteristics determined (molecular weight, substrate specificity, specificity of the peptide bond hydrolyzed, metal requirement, SH requirement, and effect of serine protease inhibitors. The enzyme has been shown to be localized in lymphocytes. Lympocytes from chopped thymus and lymph nodes of rats in various stages of EAE and Freund's adjuvant-injected controls will be prepared and the enzyme activity tested in both the broken and unbroken cells. The subcellular localization of the enzyme will be determined, and B and T lymphocytes separated from lymph nodes and the proteolytic activity measured to ascertain whether the enzyme is restricted to one cell type. Cellular and subcellular protein synthesis will be correlated with the remyelination stage in te CNS of rats severely demyelinated as a result of triethyl tin-feeding. Oligodendroglia will be prepared from spinal cords and brain stems of the affected animals by a new procedure and the rate of uptake of radioactive precursors into these cells measured. Polyribosomes will also be prepared from spinal cords of these animals and the rates of protein synthesis measured with AS-70 as a source of tRNA. These experiments will show whether increased rates of protein synthesis observed in CNS slices of rats in remyelination stages can be reflected at the cellular and subcellular level.